Is a consistent first layer across whole of A350 build plate actually possible?

Now i have solved my sloping bed issues, I continue to try and get the first layer to be the same across the entire build plate. the image below shows where I perceive I am failing. this is the print held up to a screen to act as a light box.

The source STL is Bed Level Calibration Square Grid by wsreith - Thingiverse

It is printed on a metallic PEI coated plate i purchased ages ago but have not used until today. This gives much better results than the black stock surface, maybe due to surface coating difference, maybe because it shows less deformation in the 11x11 calibration data?

  1. are my expectations too high? (i hope not as have friends who have printed this on other printers and don’t have this issue)
  2. Is anyone else able to print this 1 layer model consistently across 95% of their build volume?
  3. what else can i do to try and get consistency? (it may prevent me from doing some large format prints i plan so this not academic)
  4. why doesn’t bed levelling work well enough to counter this?
  5. is it really a bed leveling issue or a variance in extrusion over the bed?

Help?

this is the catmull mesh that was applied during the print - it was created by

  1. warming bed to 50
  2. redoing all heatedbed screws to just light finger tight (seems to give better results than tightening them all to 1.2nm as per snapmaker guidance).
  3. doing manual 11x11 calibration

i know some of you have suggested to manually adjust some of the underlying measured data points, happy to do that if someone can point me to a good guide / hand old me a bit?

note the matrix maps to the physical object so top of excel sheet is top of object pictures etc

Yea. I print across my whole sheet and find it doesn’t have any issues. I stopped testing things and just started making them.

Reminds me of telescopes. If you Just hunt for numbers, you’re always disappointed. If you just use your equipment, it’ll work

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I’ve noticed that Snapmaker’s coating on the sticker sheet is a bit too slick and makes it difficult for the first layer, extruded filament just drags across it in places because of it and sometimes even comes up and drags across into areas that would interfere with the print.

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I decided it could not be done with my bed regardless of how it is calibrated. So I went around the problem and am having great success with glass.

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Thanks, i am not surprised this works, i have a thesis the issue here is related to the ABL being used in SM2 instead of the newer UBL and the ability of ABL to create a useful mesh over such a large volume when the net difference in height between the lowest and highest point is more than 0.4mm. I assume glass is inherently flat due to it being floated during manufacturer and is rigid so doesn’t reflect inconsistencies in the build platform. Would you mind DM’ing me your mesh output form M420 V for my reference. Guess time for me to switch to glass.

Great, but the point is I do have issues and so from my perspective the rest of your reply is telling me to ignore adhesion / extrusion issues across part of my bed or you are just telling me to ignore the issue I have - hardly helpful and a little condescending that my issues don’t matter.

This isn’t about chasing numbers its about a real issue with my machine. Could you share something useful instead of anecdotes about telescopes.

What can I do to fix it and get the same experience you are having?
Can you you share your M420 V output?
What useful suggestion to fix do you have?

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I wonder if they have changed the layer over time, I have never had this issue with their build surface - if anything way to sticky, I found I have to print at lower bed temps then others recommend to avoid stickiness, especially with certain PLAs like rainbow silk.

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@scyto When comparing the surface of it compared to one of my other printers, the surface of the Snapmaker sheet really doesn’t have much “grab” to it so to speak, it’s rather slick, especially if the user doesn’t clean it prior to each print like should be done leaving body oils on it, making it hard for the initial extrusion of filament at the start of a job to actually stick where its supposed to, once it does it’s fine but a lot of the time it just drags along until it finally does grab, whereas my other printers don’t have this problem whatsoever. It’s not a problem if the nozzle is super close, but then you run into other issues, I wonder if that’s why Snapmaker tells you to set the Z offset closer than most other printers i’ve seen.

@Artezio i hear you, my experience is wholly different, i have rarely cleaned it and even then it is a damp piece of bounty kitchen roll (which I have found to be excellent at getting grease off aluminum range surrounds). I can only assume there is either inconsistent quality control in the flexible build surface or they have changed over time. What’s the offset you use on other machines?

The only place i have ever had adhesion issues on my A350 is at the edges - which is exactly where you see the issue in the picture - this is a problem when large prints start at those locations… eliminating the slope issue definitely improved matters. so it’s still possible there is something mechanical screwing me up, but no idea what!

Like I said the numbers don’t matter. I show about a 1mm difference in some of my areas. I do a 5x5. I have one of the energetic pei sheets you’re using, they’re not better than the snapmaker sheets and a lot of times worse (in my experience).

What are you printing? What material? What are your settings? Did you try printing a benchy and figuring out the material problems before trying a full print? Does the object have a solid base or does it have tiny points of contact? Did you try a brim or a raft if it has small points of contact? Cura? Luban?

I don’t mean to sound flippant. You haven’t given us enough to help you. Three calibration spot errors with those cubes doesn’t mean you can’t print the full width and breadth of your bed. It could be a model error. I had cura cut one model and it wouldn’t print a specific section correctly. Changed the orientation of the mode 90 degrees and it magically printed it correctly and the model worked.

Anyways. Hopefully that helps. I’d try an actual object and see if it works. Otherwise you’re stuck chasing stuff that doesn’t matter because you think there’s a problem because one calibration test didn’t work. My guess is whatever print you need the full bed for is going to work based on what you showed us.

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Stock set up no it’s not possible to use the full bed at any temp above ambient. I’m having a lot more successful level bed with glass but It was torture getting this to work, you can’t even clip the glass to the heated bed as it will still warp, I designed and printed my own brackets for each corner to secure the glass in place. I do miss using the snapmaker sheet as I found it great for adhering to (where the nozzle was the correct height), glass is a pain in the ass IMO. Tempted to get a pei sticker for my glass bed but I’ve had enough of throwing more money at this printer to get it to do what it should out the box. My machine will probably be getting retired from printing duties now I’ve ordered a new printer.

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I disagree; I’ve been doing multiple full bed prints. Errors from my inexperience printing? Yes. Errors from the printer? No.

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My benchies are near perfect in center of bed. I have no general materials issues. When I print say multiple benchies I have issues with those on the edge in those spots.

Tl;dr I want to print the test model I linked. I expect my $1800 printer to print what cheaper machines can with no issues. I get you think that’s unreasonable.

I have sliced in Luban 3 and 4, prusa slicer and cura with same results.
I have tried multiple nozzle and bed temps with this PLA.

Have you tried printing the model I linked at 99% of bed size? That would be a nice point of reference if you have the time.

I have a support ticket open. Will update this thread if I get a solution.

Sorry to hear you have bad experience, I have had good success with smaller prints in the centers few squares on stock plate, even with provided snapmaker PLA. But it does seem people’s experiences vary wildly.

Hey Scyto, can you post pictures of what’s what your benchies in the corners look like? You said you’ve done full bed prints with benchies and they’re messed up. It’s be nice to see how

@scyto Are you on the latest firmware? Your bed clearly sharply drops at the edges, and the calibration patches in the latest firmware would help with that.

If you already are on the latest firmware and are still having the issue you might consider shimming the platform to raise the outside. I’ve used kapton tape in the past for this since it tolerates heat and is available in 0.03mm thickness (not including adhesive thickness). The lowest spots around the edge appear to be low by about 0.2mm so 4 or 5 layers of tape (with a hole in the center) should be enough to bring it up to level.

Alternatively, you could remove the platform and check it for flatness on a table. If there’s a few supports that are low and you have a surface plate or something you could flatten it. At least a couple people on here have used the CNC head to flatten the platform also.

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I’ve been avoiding all firmware updates because Wifi barely works as it is. I’ve done a couple of larger prints now (greater than the 9x9 center squares), and without a raft it’s just a no-go on the A350 build plate. My gut answer to the question in the topic is “Nope.” because it seems unlikely that a mechanically-unskilled/under-equipped user could address this, with or without spending a significant amount (more expensive than kapton tape, less expensive than a new printer) on accessories to make the system do what it should do out the box.

All of which is a long, roundabout way to say that I’m curious to see if the firmware update fixes the problem @scyto is having.

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The firmware update definitely makes a difference. I’m doing full size prints registry now.

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Numbers do matter. Especially when the slope of my machine is so bad that I can only take advantage of half of the build plate size without something going wrong. A full calibration for me yields the front of the printer nearly printing on air, while the back of the bed has the nozzle nearly digging into the bed. Only the middle is properly printing. Maybe numbers don’t matter for you if you don’t like consistent results, but some people need more consistency out of their prints than others. I happen to be one of them. So again, numbers do matter.

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If it’s that bad then you either have an assembly error or a hardware problem/defect that is out of spec and should be covered by warranty. Especially with the error being front to back. Usually it’s the x-axis that is off and that is usually fixable by tramming.
If your sensor is working properly (and you’ve updated your firmware to fix the bug that wasn’t measuring where it thought it was) it shouldn’t be noticeably different (by eye) across the bed.
How many points are you using to calibrate?

-S